Isolation and ultrasonication of pearl millet protein: Effect on techno-functional, structural, molecular interaction, and rheological properties

In the present study, the impact of ultrasonication treatment (US) at varying time duration (10 and 20 min) on pearl millet protein (PMP) was evaluated. The native and ultrasonicated PMP were evaluated for techno-functional properties, zeta potential, particle size, SEM, FTIR, thermal properties and dynamic rheology. The significant (p < 0.05) increase in WAC, OAC, surface hydrophobicity (H₀), solubility, foaming and emulsification properties, in vitro protein digestibility, lightness (L*), and whiteness index (WI) was recorded for ultrasonicated PMP. However, with an increase in ultrasonication treatment time, enthalpies of denaturation (Δ_H) from -0.12 to -7.18 J/g and a change in denaturation temperatures (T_d) i.e. 40.87 ℃ (10 min) and 85.51℃ (20 min) was increased. Also, reduction in particle size from 4.13 μm to 2.32 μm was recorded after ultrasonication of protein samples. The ultrasonication treatment had altered the conformation and structure of PMP, which were confirmed by the results observed for surface hydrophobicity, SEM, FTIR and dynamic rheology. The changes in PMP subsequently improved i.e. solubility, surface hydrophobicity, thermal properties, and techno-functional properties.